Perforated pipe



March `Il, 1969 D. N. BLAKE PERFORATED PIPE Filed Oct. 6. 1967 qu,... .y www... ....ll I". nge..

United States Patent O 2 Claims ABSTRACT F THE DISCLOSURE A generally cylindrical pipe having corrugations extending around its circumference with elongated perforations extending in parallelism with and through the elongated crests of the corrugations on the outer side of the pipe, flanges along the sides and across the ends of the perforations, the flanges inclining outwardly of the pipe and inwardly toward a center of each perforation. A vertical section of a well casing comprising a pipe as described disposed in the ground with its axis vertical.

Well casings are conventionally encased in water bearing sand artificially placed around the casing. Particles of sand and sediment tent t-o infiltrate into the casing undesirably, and it is the object of this invention to hold this infiltration to a minimum.

Expansion and contraction of the casing or sand, and shifting of the sand for other reasons, `all cause relative movement of the casing with respect to the surrounding sand.

In the prior art, chisel-perforated pipe has been used in wells with the metal struck outwardly of the pipe, but the elongated perforations in such pipe have usually extended lengthwise of the pipe and, therefore, extended vertically in the well.

As the sand around a vwell pipe shifts with respect to the pipe, the sand is relatively free to enter a vertically elongated opening because a particle of sand has a possible entrance at any place along the length of the opening and, if deflected outwardly away from the pipe by a flange at an upper end of a vertically elongated perforation, then the sand particle still has a good chance to come back in toward the pipe and to gain entrance through a lower part of the same opening, the particle being urged into the pipe by the surrounding sand.

It is an object of this invention to provide chisel-perforated pipe in which the elongation of the opening eX- tends horizontally so that a particle of sand striking the upper side flange by a perforation will tend to become deflected outwardly beyond the opening by the side flange and will not tend as likely to enter the opening because there is so short a vertical dimension available laterally of the opening for the particle t-o enter.

In the prior art patent issued Dec. 9, 1924, to M. G. Layne, titled, Well Screen, Patent No. 1,518,696, cylindrical well casing is provided with punched -openings and a metal ribbon is spirally wound around the casing and then is struck outwardly vat each perforation after the casing has been set in the earth so that edges of the ribbon tend to form protective flanges for the opening provided between adjacent ribbons. It is an object of this inven-tion to achieve all of the advantages `above described without the necessity of altering the shape of the casing after it has been installed in the earth, as would be tremendously expensive.

It is a further object of this invention to accomplish all objectives above stated by my casing perforation area formed from a single piece of material by shaping of a single layer of the generally cylindrical casing material itself, whereby no add-itional metal ribbons need be added thereto.

In the drawings:

FIGURE 1 is a side elevation of a section of well casing of this invention.

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FIGURE 2 is a sectional view taken along the line 2-2 of FIGURE 1.

FIGURE 3 is a detail of a portion of the casing of FIGURE 1 in the area of one of the perforations.

FIGURE 4 is a sectional View taken along the line 4-4 of FIGURE 3 diagrammatically showing how a particle of sand is deflected away from the perforation by one of its side flanges.

The well casing pipe of this invention is generally indicated at 10 in FIGURE 1 and is of generally cylindrical shape having corrugations 12 extending around its circumference.

The corrugations 12 extend spirally, each defining an acute angle with respect to the elongation of the pipe and each corrugation being in parallelism with the others.

The pipe 10 has a plurality of elongated perforations 20 extending longitudinally through the elongated outwardly convex corrugations or crests 22.

The pipe 10 has flange means 26 and 28 which are elongated and which extend along the sides of the perforations 20.

The pipe further has end flange means 30, best seen in FIGURE 3, which extend substantially across the ends of the perforations 20'.

Each of the side flange means 20 and 28 inclines outwardly of the pipe and inwardly toward the center of its perforation, and the end flange means 30 may be similarly defined in their inclinations.

Between the side flanges 20 and 28 is an elongated central portion 40 of the perforation and between each side flange 20 or 28 and the adjacent edge of a respective end flange 30, a slit portion 50 of the perforation is disposed.

Referring to FIGURE 4, it will be seen that sand alongside the pipe where it is disposed in the ground when it isd disposed in the ground as a well casing has a tendency to 'attempt to infiltrate pipe and a particle of sand 60 is shown in several positions along its travel pathway 62 as the particle 60 moves with respect to the pipe during vertical shifting of sand surrounding the pipe during expansion or contraction of the pipe or of the body of sand.

The travel pathway 62 illustrates that the particle 60 would tend to become deflected away from entry into the perforation 20 by striking an upper side flange 26, being deflected outwardly.

In this way, the well casing pipe of this invention effectively prevents excessive infiltration of the pipe by sand particles.

As thus described, the pipe of this invention is believed to lend itself to economical manufacture and to act as an effective deterrent to infiltration.

In the claims:

1. A generally cylindrical pipe having corrugations extending around its circumference, said pipe having a plurality of elongated perforations extending longitudinally through t-he elongated outwardly convex corrugations, said pipe having elongated flange means along the sides and across the ends of said perforations, each said side flange means inclining outwardly of said pipe and inwardly toward a center of its perforation.

2. A vertical section of a well casing comprising a pipe as described in claim 1 disposed in the ground with its -axis vertical.

References Cited UNITED STATES PATENTS Re. 2,965 `6/ 1868 Mack 175-314 X 1,027,917 5/ 1912 Smith. 1,268,366 6/191'8 Layne 166-231 X 1,518,696 12/ 1924 Layne 166-23'3 DAVID H. BROWN, Primary Examiner. 

